Modeling and Experimental Study of the Electron Transfer Kinetics for Non-ideal Electrodes Using Variable-Frequency...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Understanding electron transfer is key for designing hybrid electrocatalysts.
• Heterogeneous materials with reversible redox behavior present challenges in kinetic analysis.

Purpose of the Study:

• To develop a general simulation-based approach for interpreting variable-frequency square wave voltammetry (VF-SWV).
• To accurately determine kinetic parameters for heterogeneous electrocatalysts.

Main Methods:

• Applied resistive and capacitive corrections and frequency domain analysis.
• Utilized statistical treatment of surface redox kinetics.
• Validated the approach using Co tetraphenylporphyrin (CoTPP) on carbon cloth and CNTs for CO2 electroreduction.

Main Results:

• The simulation approach successfully determined surface double layer capacitance (C), uncompensated resistance (Ru), symmetry coefficients (α), kinetic constants (k0), and redox potentials (E0).
• The method revealed a stochastic map of redox kinetics, highlighting the inhomogeneous nature of the electrochemically active layer.
• Computed parameters showed excellent agreement with cyclic voltammetry and known CoTPP catalytic activity.

Conclusions:

• Variable-frequency square wave voltammetry (VF-SWV) is a suitable technique for studying complex materials like covalent organic frameworks and organometallic-CNT mixtures.
• The insights gained are valuable for developing catalyst-support interfaces and immobilization strategies.
• This method aids in the rational design of modern hybrid electrocatalysts.